Leukemic pulmonary infiltration, as an initial presentation of acute leukemia, is rare and poses a therapeutic dilemma. Leukemic infiltrate of the lung may be unrecognized, as patients can present with cough, fever and localized roentgenographic infiltrate, all suggestive of bacterial pneumonia. Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML) with distinct clinicopathologic features, such as: younger age of patients, shorter duration of symptoms before diagnosis, pulmonary infiltration with atypical promyelocytes and bleeding tendency due to disseminated intravascular coagulation (DIC). APL can become rapidly fatal if not treated early in its course. We report a case of APL with diffuse pulmonary infiltration and abnormal complete blood count. He was initially diagnosed and treated as an outpatient for community-acquired pneumonia. The patient returned with worsening pulmonary infiltrate, abnormal peripheral smear and respiratory failure, resulting in death within three months of his initial presentation. As evidenced by this case, acute leukemia should be considered in the differential diagnosis for pulmonary infiltrate and abnormal hematological findings.